#!/usr/bin/env python2
import lab1, itertools

for x in lab1.powerset(set('xy')): print x
for x in itertools.combinations(set('xyz'), 2): print x

def print_values(n, values=lab1.odd_naturals):
    for x in values():
        if abs(x) < n:
            print x,
        else:
            print
            break

print_values(20, lab1.even_integers)
